1. Field of the Invention
The present invention relates to a liquid transporting apparatus which transports a liquid.
2. Description of the Related Art
Liquid transporting apparatuses in various fields, which include a piezoelectric actuator which applies a pressure to a liquid have hitherto been known. For example, in U.S. Pat. No. 6,648,455 (corresponds to Japanese Patent Application Laid-open No. 2002-59547), an ink-jet head which includes a piezoelectric actuator which applies a pressure for jetting the ink from nozzles has been disclosed.
This ink-jet head includes a channel unit (called as a cavity plate) in which ink channels such as a plurality nozzles and a plurality of pressure chambers which communicate with the nozzles are formed, and a piezoelectric actuator which is joined to the channel unit to cover the plurality of pressure chambers. Moreover, the piezoelectric actuator has a plurality of piezoelectric layers (piezoelectric sheets) which are stacked, and individual electrodes and common electrodes which are arranged in areas facing the pressure chamber, sandwiching each of the piezoelectric layers in thickness direction-thereof. Moreover, when a voltage is applied between the individual electrodes and the common electrodes and an electric field in the thickness direction is generated in the piezoelectric layer sandwiched between the individual electrodes and the common electrodes, the piezoelectric actuator changes a volume of the pressure chamber by using a deformation (piezoelectric distortion) occurred in the piezoelectric layer, and applies a pressure to the ink in the pressure chamber.
Furthermore, the piezoelectric actuator disclosed in U.S. Pat. No. 6,648,455 is joined to the channel unit by an adhesive sheet (an adhesive layer). Here, the adhesive sheet is made of a synthetic resin material, and is provided on an entire joining surface of the piezoelectric actuator including the area facing the pressure chamber. Moreover, when the piezoelectric actuator is joined to the channel unit by the adhesive sheet, the adhesive layer in the area facing the pressure chamber functions as an ink isolating film, which prevents the ink in the pressure chamber from permeating into the piezoelectric layer.
In the piezoelectric actuator for an ink-jet head disclosed in U.S. Pat. No. 6,648,455, the piezoelectric layer and the ink in the pressure chamber are isolated by the adhesive sheet formed of a synthetic resin material. However, generally, a synthetic resin material has low ink permeation inhibiting property (ink barrier property) Moreover, a synthetic resin material is degraded with a period of use becoming long, and there may be a damage such as a crack and a scratch. Furthermore, when the ink in the pressure chamber permeates into the piezoelectric layer through the damage on the adhesive sheet formed of a synthetic resin material, there is a possibility of a short (short-circuit) occurring between the adjacent individual electrodes or between the individual electrodes and the common electrodes which are provided on the piezoelectric layer.